It is proposed to investigate regeneration of goldfish optic axons with the following specific aims: I. To examine the role of phosphorylation of axonally transported proteins by investigating (a) the nature of the changes in protein phosphorylation that occur during regeneration; (b) the protein kinases responsible for these changes; (c) how agents that modulate protein phosphorylation affect regeneration, and (d) how alterations in the time course of regeneration affect the sequence of changes in phosphorylation. II. To determine how some axonally transported constituents involved in synaptic function change during regeneration, particularly with respect to whether or not the regenerating axons have formed retinotopically correct connections. The constituents to be investigated would be synapsin I, nicotinic acetylcholine receptors (defined by alpha-bungarotoxin binding), and acetylcholinesterase. III. To investigate the role of phosphorylation of proteins in the interaction between axons and glial cells, based on our observation that when the axons have degenerated the glial cells do not phosphorylate the same array of proteins as when the axons are intact. Major techniques in this study would be the analysis of phosphorylated proteins by 2-dimensional gel electrophoresis and HPLC, applied to studies of regenerating axons and studies of glial cells in vivo and in vitro. The overall objective is to analyses the properties of a successfully regenerating neuron, in order to further our understanding of the process of axonal regeneration and the mechanisms involved in its regulation. The ultimate application of this knowledge would be in developing techniques for promoting regeneration following damage to the central nervous system produced by conditions such as spinal cord injury, stroke or cerebral palsy, and would also have relevance for studies of Alzheimer's disease.